1. Field of the Invention
This invention relates to a socket for an electric part or component such as an IC, etc., and more particularly to a socket for an electric part including a contact shutter member for displacing contacts which are arranged on the socket body in order to be contacted with terminals of an electric part between a first position (hereinafter referred to as the "contact position") where the contacts are contacted with the terminals and a second position (hereinafter referred to as the "release position") where the contacts are no longer contacted with the terminals.
2. Brief Description of the Prior Art
An IC socket disclosed in U.S. Pat. No. 4,623,208, includes a socket body and a contact shutter member mounted on an upper part of the socket body in such a manner as to be movable upward and downward. The contact shutter member, when pushed down, displaces the contacts backward against elasticity to form a contact released state relative to IC terminals so that an IC can be inserted and removed with no load in that state. The contacts, when the push-down force of the contact shutter member is released, are displaced forward in compliance with the elasticity of the contacts to come into contact with the IC terminals in such a manner so as to exert a downward force to a bent portion of each of the IC terminals while pushing up the contact shutter member.
In the above-mentioned socket, the contacts are displaced forward in compliance with the elasticity and receive a contact pressure by being elastically pushed against the surfaces of the IC terminals which are held in a laterally stationary state. The reliability of the contact relation between each of the corresponding IC terminals and contacts depends on only the elasticity of these contacts.
On the other hand, high density arrangements of IC terminals has progressed in recent years, and miniaturization of contacts is required more than ever. If the contacts are miniaturized, however, the elastic coefficient inevitably becomes small, weakening the function thereof against the IC terminals and thus lowering the contact pressure. As a result, a problem arises in that it is difficult to obtain a highly reliable contact relation only by means of the elasticity of the contacts.
Further, although it is desirable that the contact shutter member can be operated with as small a push-down force as possible, the reduction of operating force in the conventional example also results in the reduction of the elastic force of the individual contacts, thereby lowering the contact pressure. In other words, in the conventional example, it is difficult to reduce the push-down operating force of the contact shutter member while maintaining the contact pressure the (elastic forces of the contacts).
The present invention has been accomplished in order to obviate the above-mentioned disadvantages inherent in the prior art.